A Relay Feedback Method for the Tuning of Linear Active Disturbance Rejection Controllers

Abstract

Active disturbance rejection control (ADRC) is a new control method that estimates the total disturbance by an extended state observer and compensates it by a state feedback law, and good disturbance rejection performance is expected compared to traditional PID control method. However, the parameters of ADRC are hard to tune, even for linear ADRC (LADRC). This paper proposes a new tuning method for second-order LADRC based on relay feedback, which is simple to implement without knowing the information of the controlled plant. Simulation examples show that the proposed method can achieve good performance in disturbance rejection and robust performance. The tuning rule is also tested for the control of a steam condenser. Compared with PID, the proposed method has smaller overshoot and shorter settling time.

Keywords

• Relay feedback
• ultimate point
• linear active disturbance rejection control (LADRC)
• parameter tuning
• first-order process with deadtime process (FOPDT)